This invention relates to an electric shutter device for a focal plane shutter.
There has heretofore been itilized a notched gear for disconnecting engagement between the film winding system and the shutter moving system upon completion of the shutter charging operation. Further, there has also been utilized a modified construction of such electric shutter device wherein, for reducing the mass of the shutter moving member, even a counterpart gear to be meshed with the notched gear is excluded from taking part in the shutter movement. The detailed construction of this latter-mentioned device is such that a return spring is hooked onto the counterpart gear so that it may be returned by this return spring to its positional state prior to shutter charging, when the engagement between the notched gear and the counterpart gear is released, i.e. upon completion of shutter charging.
Incidentally, in the electric shutter device in the focal plane shutter, it is necessary to take various measures such as opening of a trigger switch prior to the shutter opening, closing of an FP contact for flash synchronization, or producing a warning signal for battery consumption so as to compensate for delay in de-magnetization of a control magnet. (Such functions will hereinafter be generally called "pre-shutter release action").
However, the abovementioned counterpart gear rotates to return to its pre-shutter charging state irrespective of the shutter release operation, on account of which the energy stored in the return spring is wasted.